FR2838658A1 - PRODUCT FOR CLEANING REFRIGERATING PLANTS, METHOD AND DEVICE FOR IMPLEMENTING IT - Google Patents

Abstract

The invention relates to a cleaning fluid for a refrigeration installation, characterized in that it comprises a cleaning oil mixed with a liquefied transport gas with which it forms a cleaning foam by expansion. The oil is for example a POE or else a PAG is R134a gas. The invention also relates to the cleaning method. This comprises the following steps: creating a foam from the oil and a liquefied gas in which it is at least partially miscible, circulating the foam in said element, extracting the foam. In particular, the installation is rinsed with the gas separated from the cleaning foam to remove oil residues.

Description

elastomer playing both the role of obstruction element and element

pressure.

  The invention relates to the field of refrigerating installations in which a refrigerant circulates in closed circuit. Wile aims in

  particularly a means for cleaning the equipment.

  The installations concerned by the present invention comprise a closed circuit in which circulates a refrigerant entrane by means of a compressor type lubnfie. Due to the lubrication requirements of the compressor, there is introduced, as is known, a lubricating oil. o The proper functioning of the installation is conditioned by a good condition of the inner surfaces of the circuit. It is up to the operator to remove impurities that may be entrained by the refrigerant. At the origin of the formation of its impurities, one finds the incidents of operation of the engine in hermetic units or hermetic accessible and the resulting formation of calamine, the presence of water in the circuit, the formation of acid, the degradation of the lubricating oil or the formation of oxides to welds and solders when they have been carried out without the prior release of oxygen trapped in

ducts.

  A cleaning operation is therefore necessary already at the start of a new installation or later after repair of a breakdown

  causing the contamination of the circuit.

  The Applicant has hitherto used for these cleaning operations a product of the R141b type, that is to say a 1,1-dichloro, 1-fluoroethane, having a good solvent power (IKB = 51), of low surface tension (18.4 mN / m) which is suitable for cleaning metal surfaces, plastics and composites. It is not flammable in the liquid state and is

  packaged in 28 kg bottles pressurized with anhydrous nitrogen (7 bar).

  To clean, reline the liquid outlet of the bottle a

  The element of the installation to be cleaned, for example a tubular exchanger.

  The output of the clement is relined to a recovery keg by means of a flexible tube. This keg is itself maintained at atmospheric pressure by being relic in the open air by a pipe which allows to evacuate the nitrogen and the possible vapors of product. The venting is sufficient because the product has a low vapor pressure under the conditions of use, its boiling temperature being higher than C. The cleaning operation consists of circulating the fluid by opening the tap. from the bottle. The fluid is then propelled by the gas under pressure. Eventually activates the circulation by creating shots in the fluid, opening and closing the valve repeatedly and quickly. We stop the fluid supply when the liquid

  recovered in the cask flows clear. The installation is clean.

  Due to the entry into force of regulations restricting the use of HCFC fluids, the use of a substitute product has become necessary. The replacement product must have the same properties as the previous one. It must be a solvent for the products used in the installations, not to be flammable under the conditions of use, to be extractable, to have a low viscosity, not to leave residues traces or to the rigorous traces compatible with them. refrigerants and oils

  lubrication used in the refrigerant circuit. It must be inexpensive.

  Cleaning oils based on polyol ester (POE) or polyalkylene glycol (PAG) are known, which have the decapping properties and the low viscosity required for this application. Wiles wind additionally compatible with the refrigerant used in the circuit. They are used in particular to convert plants to new refrigerants. In circulation in a closed circuit, the quantity is of the order of 1%, 3% at the most. However their implementation in cleaning operations, or they are used in larger proportions, is not satisfactory because they are very difficult to extract from the circuit. In addition, there is a residue of non-extractable oil that can affect the proper functioning or even cause breakage

of machine.

  The invention therefore relates to a cleaning fluid for installation

  refrigerant which does not present this inconvenient.

  In accordance with the invention, the cleaning fluid is characterized by comprising a liquid cleaning oil in admixture with a carrier gas with which it forms a detergent foam. Advantageously, the transport fluid is based on hydro fluoro-carbon. In particular, it is the product R-34a (tetrafluoro 1,1,1,2 ethane) and the cleaning agent is a POE or PAG oil. other

  o products concerned by the invention.

  For example, in addition to R-134a, the following fluids may be used: R125, R-245fa, R-245ca, R-236ea, R-236fa, RC318 alone or a mixture containing these fluids: R-404A, R- 404B, ..., R-404E, R-413A, R-417A, R 507. The R-134a fluid is, however, the most appropriate fluid for

present application.

  In accordance with another characteristic, the cleaning fluid is comprised of from 10 to 80% cleaning oil and from 90% to 20% of liquefied gas. Preferably it consists of 20 to 40% of cleaning oil and

from 80 to 60% of liquefied gas.

  This cleaning fluid by its implementation in the form of a foam, has the advantage, in addition to its solvent power, to act mechanically

  s to detach and drive the impurities of the circuit into which it is injected.

  Furthermore, in this form, the amount of cleaning oil contained in the circuit is limited during the cleaning operation and therefore the amount of residue product! that it is necessary to extract after cleaning. In addition, liquefied gas can be used to flush the

  circuit due to its miscibility with the cleaning agent.

  Advantageously, the fluid is conditioned in a pressurized container, at least 4 bar, at most 10 bar, so that it forms a

  foam when extracted from it.

  The invention therefore also relates to a method for cleaning a refrigerating plant. This is characterized by the fact that it comprises the following steps: to create a foam from the oil and a fluid of

  transport, circulating the foam in said element, extract the foam.

  In accordance with another characteristic, the extraction step is carried out by circulating in the element to be cleaned a miscible extraction fluid, at least in part, with the cleaning oil. In particular, the extraction fluid is formed of the transport fluid which has been separated from the foam. This process has, among other advantages, that of

  to operate in closed circuit, under rejection of the atmosphere.

  According to a preferred embodiment, after extracting the foam from the element, it is collected in a recovery vessel, and the transport fluid is circulated in said element by means of a transfer machine. The transport fluid is extracted in gaseous form to said container and then liquefies before its injection

  in the refrigeration plant.

  Preferably, the method comprises an initial step of communication with a source of vice. I1 also includes a final step

  bleed by means of the transfer machine.

  The invention also relates to a device for implementing the method by means of a cleaning fluid. It comprises a source of cleaning fluid, a cleaning fluid recovery means, conduits matching said source with an inlet of the refrigerating plant element, conduits communicating an outlet of the heating element. to clean with the means of

  o recovery, and valves controlling said links.

  Advantageously, it comprises a transfer machine, which can be interposed by means of valves between a gas outlet of the recovery means and the entry of the station to perform the rinsing step. In particular, the device comprises a defective pump that can be connected to the valves by means of the entire cleaning circuit for a defect. In a preferred embodiment, the device comprises a block composed of said valves with means for connection to at least the source of cleaning fluid, the recovery means, a transfer machine, a vice pump or the element of [ refrigeration system to be cleaned. The invention will be described in detail, showing other features and advantages, with reference to the accompanying drawings in which - Figure 1 schematically shows a cleaning device of a refrigeration plant, and - Figures 2 to 4 represent the different cleaning phases with the

circulation of fluids.

  Referring now to FIG. 1, there is an element of a refrigerating plant F to be cleaned. Here, there is shown a serpentine-shaped pipe, with an inlet F1 and an outlet F2. The invention is not limited to the cleaning of a single element; all or part of an installation can be cleaned The source of cleaning fluid is represented by a BF bottle. Wile has a tap BF1 to control the extraction of the cleaning fluid FN whose volt liquid phase and the gas or vapor phase represented by transparency. The valve controls the passage through a dip tube in the liquid phase. The cleaning fluid is

  a mixture of cleaning oil and liquefied gas.

  The purpose of the cleaning agent is to solubilize the lubricating oil to be extracted, to entrain the water and the acids, as well as the contamination products. The cleaning oil is a synthetic oil, of

  preferably based on polyol ester (POE) or polyalkylene glycol (PAG).

  These products are commercially available for POE, for example under the brand names Planetelf ACD of the company Totalfinaelf, Arctic EAL de

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  the company Exxon Mobil or Emkarate RL of the company ICI-Emkarate, and for the PAG, for example under the brand names Planetelf Pag488, Planetelf Pag244 and Planetelf Pag Sp20 of Totalfnaelf or Emkarox RL de Ici

  Emkarate. It may also be an alkyl benzene or a mineral oil.

  s This agent is not volatile. It is of low viscosity under the conditions

  of use, up to 68 centistokes at 40 C in practice.

  The liquefied gas must have a boiling temperature at ambient pressure

  less than 20 C and preferably less than -20 C or lower still.

  o However, it becomes more expensive and less interesting economically. The cleaning oil is mixed with the liquefied gas in which it is miscible. A minimum amount of agent is required in the mixture to obtain a foam and a minimum amount of gas to obtain a

  pressure. The rate is between 10% and 70% of cleaning oil.

  However, in practice, a mixture of 20% of cleaning oil is advantageously used for 80 to 60% of liquefied gas. R-134a fluid

is the preferred liquefied gas.

  Next to this bottle, there is shown the cleaning fluid recovery means which is also a bottle BR. This includes two valves, BR1 and BR2. The valve BR1 controls the passage through a tube immersed in the liquid phase of the recovered fluid, and the valve BR2 s controls the passage through a shorter tube communicating with the

gas phase of recovered fluid.

  An autonomous transfer machine T comprises a pump which is preferably a dry piston or a diaphragm piston, TP, because it does not require any lubricating oil. The use of an open compressor hermetic or hermetic accessible is possible but we are confronted with the risk of pollution, and it requires a monitoring of the oil level. Wile also includes a ventilated TE exchanger. The fluid to be transferred, initially to the vapor state, is admitted internally via a inlet T 1 which is provided with a filtering means T3. It passes successively through the pump and then into the exchanger where it is cooled

  until the action and is evacuated by the output T2.

  The device of the invention comprises a block V having 6 valves V1 to V6, and internal conduits communicating six pipe connectors: VT1, VBR1, VE2, VBR2, VT2, VET, W. VBF. By block is meant any assembly comprising the various organs. These can be mounted on a support plate for example. Two-way wind valves with manual control. The valves V1, V3 and V5 wind placed

  o In addition, valves V2, V4 and V6 also.

  The valve V1 is placed in series with the connection VE2 of one dimension and with the valve V5 of the other. The valve V5 communicates with the valve V3 which is connected to the VBF connection. Above, the V2 valve is in series with the VBR2 fitting on one side and with the V4 valve on the other. This communicates with the valve V6 which is connected to the connection W. The connection VBR1 corresponds with the duct connecting the valves V1 and V5, the connection VT2 with the duct connecting the valves V5 and V3, the connection VT1 o with the duct connecting V2 and V4, and the VE1 connection with the duct connecting V4 and V6. A conduit port leads between

  valves V4 and V6, and the conduit fits between the valve V3 and the fitting VBF.

  The connections allow the connection of external pipes, for example flexible pipes, to put them in communication with the various valves of

  the way explained further. Fittings can be fast type.

  The C1 pipe connects the valve BF1 of the cleaning fluid bottle to the VBF coupling; the pipe C2 relic the valve of the recovery bottle BR1 to VBR1; the pipe C3 connects the valve BR2 to VBR2; the pipe C4 connects the connection VE2 to an inlet F2 of the element to be cleaned; the connecting pipe C5 VE1 has another F1 inlet of the element; the pipe C7 relic VT2 has the output T2 of the transfer machine; the pipe C6 relic VT1 has [entry T1 of the

  transfer machine. Finally the C8 pipe relic W has a PV defect pump.

  The cleaning of an element of a refrigeration plant is carried out in the following manner. The connections were made as shown in Figure 1. All firm vent valves. A heating jacket is placed around the bottle B in order to maintain it at a temperature of between 20 ° C. and 50 ° C. as a function of the ambient temperature. The bottle contains, for example, 30% POE oil and 70% of a liquefied gas such as R-134a which by defending through the oil is likely to foam. The selected liquefied gas also presents the

  property to be miscible with the cleaning oil.

  The operation is initialized by placing the entire circuit in the preliminary condition. The taps of the bottles wind firm. The six valves are opened and the PV pump is started. Vice does not need to be pushed; when the manometer of the pump indicates - [bar, the valve V6 is closed, and

if the pump is stopped.

  The flow of fluids during the cleaning phase appears in Figure 2. The valves V2, V3, V4, V5 and V6 wind closed. Valve V1 remains open. The tap BF1 is opened. This has the effect of allowing the natural gas to relax. Passing through the FNL liquid phase, it forms a foam. The foam formed from the oil-gas mixture is thus propelled into the circuit which is in depression. A few moments later, the time that the pipes are filled, we open the valve BR1 of the recovery bottle. The foam expelled from the bottle BF travels through the ducts C1 and C5 before entering the installation element. Irlgorlllque. The combined effect of POE oil, pickling and detergent, and abrasive foam allows the detachment of particles or waste adhering to the walls. The circulation and state of the fluid can be monitored by observing the LEDs located at the two VBF and VBR1 connections. When the fluid has a sufficiently clear appearance, stop the phase of

  cleaning by closing the valve BF1.

  Rinsing is then carried out to remove the remaining foam of cleaning oil which may have settled in the circuit. We are now referring to the

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  Figure 3. Valves V4, V5 and V6 are closed. The valves V1, V2 and V3 are opened as well as the valve BR2. A heating jacket is placed around the bottle BR to promote the vaporization of the liquefied gas from the mixture collected in the bottle. For the R-134a gas, it is sufficient to heat to 30 C. The compressor TP of the transfer machine is started. The machine sucks up the gas phase of the bottle BR. Wile therefore understands only the gas separated from the oil. Wile follows the ducts C3 and C6, enters the machine through the filter T3, is compressed by the piston of the compressor self-lubricates and then cooled in the exchanger TE,

o enough to liquefy.

  The liquefied gas travels through the conduit C7 and passes through the element F. Because of its miscible nature with the cleaning oil, and because it is at the inlet of the element with an oil level close to zero, it absorbs all traces of oil that it meets in the circuit, until saturation. It is then returned to the recovery bottle BR or the liquid phase settles at the bottom. The rinsing is continued until no more foam is percolated.

through the LED of the VBR1 fitting.

  o The cleaning operation is completed by purging the ducts. Figure 4 shows the flow of fluids. The BR2 valve of the recovery bottle, the valve BF1 of the cleaning fluid bottle, and the valves V1, V3 and V6 are closed. Valves V2, V4 and V5 are opened. We put in action the transfer machine. The created depression aims at emptying all the ducts and the element of the refrigeration plant. The mixture is forced back by the compressor of the transfer machine into the recovery bottle. The machine is stopped when its manometer indicates a given pressure that is considered satisfactory, for example

0.15 bar relative.

  The set is then ready for a new start.

  We have described a way in which the valves are manually controlled. The invention also applies to the case where the order is

  s managed automatically by means of solenoid valves.

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  Several attempts were made to validate the process using a product

  composed of POE oil and R134a fluid.

  The measured values of the saturated vapor pressure for different compositions and at different temperatures are reported in the table below. Composition% by weight _ Oil 5 10 30 14 60 70 80 90 R134a 95 90 70 160 40 30 20 10 Temperature Relative pressure exerted in bar

  0 C 0.4 0.7 1.4 1 1.5 1 1.6 1 1.7 1 1.75 1 1.8

 C 1 1.8 3.3 3.7 4 ,! 4.3 4.4 4.5

 C 1.9 2.7 4.7 5.7 5.9 6.2 6.4 6.5

   C 2.5 4.2 8.4 9.5 1 1.1 1 1.6 1 1.9 12.1

  o The storage mixture is a single-phase liquid at all temperatures between 0 C and 50 C and all proportions tested. The foaming effect of the mixture is strong when it has between 10 and

  % of oil. It decreases rapidly outside these proportions.

  We used a mixture whose proportions were 1/3 POE oil and 2/3

of R134a.

  - Cleaning a new window air conditioner.

  o The volume of the refrigerant circuit is 4 liters. The fluid is entrained by

hermetic compressor.

  The product circuit was filled by circulating it in the normal direction of operation of the machine. The product was recovered at the outlet of the suction pipe and accumulates in the recovery bottle through a transparent PVC hose. We could visualize

  the state of the fluid at the output of the circuit. 5 kg of product was used.

  After cleaning, there was about 0.6 kg of product to be recovered in the installation, ie 0.2 kg of oil. The rinsing procedure of the invention was applied using a transfer machine (RD2000 mark) for about 16 minutes. This corresponded to the passage of 0.7 kg of R 134a,

  sufficient quantity to absorb the oil.

  The plant was then purged and closed the valve of the recovery bottle. Operation was stopped when the manometer indicated 0.2

relative bars.

  At the weighing of the apparatus, no appreciable difference was observed in relation to the situation before the treatment. This means that the oil has been recovered.

  - Cleaning an evaporator of 14 tubes on 4 ranges.

  The volume of the circuit was 4 liters.

  The product circuit was filled by circulating it in the normal direction of operation of the machine. The product was recovered at the outlet of the recovery pipe by means of a transparent hose

  PVC. It was found that the circuit was heavily fouled.

  In order to facilitate the flow of the product into the circuit and to obtain sufficient pressure for the cleaning product, the bottle is heated to

way of a radiator.

  o 3.8 kg of product was used before obtaining a clean foam at the outlet.

  After cleaning, about 0.3 kg remained in the evaporator. it

corresponds to 0.1 kg of oil.

  The cage was rinsed according to the invention for about 8 minutes. This time corresponds to the passage of 0.35 kg of R134a, enough quantity to absorb the oil. The installation was purged as before. Through

  peace, we checked that the oil was recovered.

  - Cleaning a negative cold room.

  The installation included an evaporator with a finned battery, o Morgana brand and a Copeland compressor with a capacity of 18.13 m3 / h. The

  volume of the circuit was 28 liters and that of the room was 5 m3.

  The circuit included 3.5 kg of FX10 which is a transition fluid.

  The compressor, the anti-liquid bottle and the oil separator were separated to clean them apart. The thermostatic expansion valve has been removed and replaced by a breather tube ahm to ensure a good

  feed rate. The dehydrator was also replaced by a tube.

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  We proceeded as in the preceding cases. The circuit was not heavily soiled. 19.29 kg of product was needed. There remained 8 kg to recover. The procedure was rinsed according to the same procedure as the previous cases, during lh30, that is to say 8 kg of R134a. After purging the circuit, we found that we recovered 19.1 kg of 19, 29 injections. We think that

  the gap came from fittings that were not tightly sealed.

Claims (12)

  1.- Cleaning fluid for a refrigerating plant, characterized in that it comprises a cleaning oil mixed with a liquefied gas of   transport with which it forms by relaxation a cleaning foam.   2. Fluid according to the preceding claim wherein the liquefied gas has a boiling temperature at atmospheric pressure less than 20 C,   o preferably less than - 20 C.   3.- Fluid according to claim 1 or 2, the liquefie gas is based on hydro-fluoro-carbon. -   4. Fluid according to claim 1, 2 or 3, wherein the oil is miscible with   at least 10% in the liquefied gas, especially between 15 and 40%.   5. Cleaning fluid according to one of claims 1 to 4, wherein the   gaseous transport fluid is selected from the products R-134a, R-125, R   245fa, R-245ca, R-236ea and R-236fa, alone or in a mixture.   6. Cleaning fluid according to one of claims 1 to 5, wherein   the cleaning oil is a synthetic oil, especially POE type, PAG or alkyl benzene.   7.- cleaning fluid according to one of the preceding claims,   It consists of 20 to 40% of the cleaning oil and 80 to 60% of liquefied gas.   8. Cleaning fluid according to one of the preceding claims,   packaged in a pressure-resistant container, so that it forms a foam when it is removed from the container to be put into   circulation in the room to be cleaned.   9. A method of cleaning an element of a refrigeration plant by means of a cleaning oil, characterized in that it comprises the following steps: creating a foam from the oil and from a liquefied gas in which it is miscible at least in part, circulating the foam   in said element, extracting the foam.   10. Process according to the preceding claim, in which the extraction stage is carried out by circulating in the element a fluid.   of miscible extraction, at least partly with the cleaning oil.   11.- Method according to the preceding claim wherein the fluid   o of extraction is formed, at least in part, to said liquefied gas.   12.- Method according to the preceding claim, wherein after extraction of the element foam, it is recovered in a recovery vessel, the gas phase is extracted which is circulated s in said element 13 Process according to the preceding claim, according to which said gaseous phase is extracted by means of a transfer machine by means of which the   gas is liquefied before being circulated in said element.   14.- Method according to one of claims 9 to 13, comprising a step   initial communication with a source of vice.   1S.- Method according to one of claims 13 and 14, comprising a step   Final purge by means of the transfer machine.   16.- Device for implementing the process according to one of the   by means of a cleaning fluid according to one of the   Claims 1 to 8, comprising a source of cleaning fluid, a   means for recovering the cleaning fluid, conduits communicating said source with an inlet of the element to be cleaned, conduits communicating an outlet of the element to be cleaned with the recovery means, and valves controlling said bets; in communication. 17.- Device according to the preceding claim, comprising a transfer machine that can be interposed by means of valves between a gas outlet of the recovery means and the input of the element to perform   the step of rinsing with liquefied gas.   18.- Device comprising a defect pump that can be placed in communication by means of valves with the whole of the circuit of cleaning for a defect.   19. Device according to one of claims 15 to 18 comprising a block   composed of said valves with connection means to at least one of the following organs: the cleaning fluid source, the recovery means, a transfer machine, a vacuum pump or the   refrigerating plant to be cleaned.